volatile recycling at subduction zones terry plank, lamont doherty earth observatory the subduction...
TRANSCRIPT
Volatile Recycling at Subduction Zones
Terry Plank, Lamont Doherty Earth Observatory
The Subduction Factory
Is the Ocean Shrinking?
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
60% ofstructurally-bound H2Oreleased
Hacker (2008) G3; Jarrard (2003) G3
Water Fluxes During Subduction
QuickTime™ and a decompressor
are needed to see this picture.
60% ofstructurally-bound H2Oreleased
Hacker (2008) G3
Water Fluxes During Subduction H2O Output? H2O % in magmaMagma Mass Flux
0 1 2 3 4 5 6 7 8
Centam
H2O (least degassed) wt%
Arc Data: 2000
MORB
(SubFac Science Plan)
0 1 2 3 4 5 6 7 8
Aleutians
Centam
Marianas
Mexico
Tonga
Kamchatka
H2O (least degassed) wt%
Arc Data: 2009
MORB
3.9 wt% H2O +/- 1.0 (1 stdev)
Average Arc Growth Rates
QuickTime™ and a decompressorare needed to see this picture. QuickTime™ and a decompressor
are needed to see this picture.
Suyehiro et al. (1996) Science
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
Holbrook et al (1999) Geology
(km3/km/Ma)
Izu Arc
Aleutian Arc
23-33 (Reymer&Schubert, 1984)
75-82 (Holbrook et al., 1999)
59-61 (Dimalanta et al., 2002)
89-182 (Jicha et al., 2006)
Duration: 46 Ma
28 (Reymer&Schubert, 1984)
66 (Suyehiro et al., 1996)
56-60 (Dimalanta et al., 2002)
Duration: 47 Ma
QuickTime™ and a decompressor
are needed to see this picture.
Th input (g/yr)
Th output (g/yr) = CTh * Magma Mass Flux
Hebert et al (2009)
100 km
QuickTime™ and a decompressor
are needed to see this picture.
60% ofstructurally-bound H2Oreleased
Hacker (2008) G3
Water Fluxes During Subduction 4 +/- 1 wt% H2O arcs60 +/- 20 km3/km/Ma3.0E8 = 40 +/- 20% recycled to arc
0 300 600
Millions of years before present
200
400
600
800
1000
Relative sea levelchange (meters)
70%
40%
50%
Subduction of Water Lowering Sea Level
50% water recycled to surface
from Rupke et al. (2004)
Millions of years before Present
Global Sea LevelVariations
met
ers
Hallam (1982); and Wallman (2001)
Sea level fallover past ~ 600 Madue to subduction ofwater??
from Rupke et al, Earth and Planetary Science Letters (2004)
SizeofOcean
today
Oceangrowing
Oceanshrinking
hottermantle
coolermantle
QuickTime™ and a decompressor
are needed to see this picture.QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
2% H2Oin 4 km mantle 5.7
QuickTime™ and a decompressor
are needed to see this picture.
All serpentine-bound H2Obypasses arc?Hacker (2008) G3
Water Fluxes During Subduction
QuickTime™ and a decompressor
are needed to see this picture.
2% H2Oin 4 km mantle 5.7
pastarc
0.5
2.5
5.4
Lose oceanIn 1.7 Ga!
QuickTime™ and a decompressor
are needed to see this picture.
Wiens/Lizarralde MARGINS experiment
Subducting Carbonate and CO2 Cycling
GLOSS - global subducting sediment
Plank & Langmuir (1998)
Centam
Plank, et al (2002) Geology
Altered oceanic crust
Alt figure??
(1999) GCA
CO2 Output??
Figure from Wallace (2005) JVGR
Melt Inclusions - minimum CO2
QuickTime™ and a decompressor
are needed to see this picture.
?
Benjamin et al. (2007) JVGR -- Irazu Volcano, Costa Rica
Global Flux Estimates from Wallace (2005) JVGR
C Flux in & out of the mantle
(Alt & Teagle, 1999; Sleep & Zahnle, 2001; Jarrard, 2003)
Courtesy of M. Hirschmann
Input Output
25%
Centam, CO2 flux from slab
Gorman et al (2006) G3
Shaw et al (2003) EPSL
QuickTime™ and a decompressor
are needed to see this picture.
QuickTime™ and a decompressor
are needed to see this picture.
Typical CO2/3He in Centam despite major carbonate subduction
H2O Recycling
QuickTime™ and a decompressor
are needed to see this picture.
REE/Th
CO2 Recycling
QuickTime™ and a decompressor
are needed to see this picture.
• 40-60% returned to arc
• serpentine subduction?
• 25% returned to arc
• decarbonation?
• CO2 fluxes out volcanoes